CERTAIN SPECIES OF Mucor 295 
7. Mucor pLuMBEus Bonorden (sense of Lendner), Abh. Naturf. 
Ges. Halle 8: 109. pl. 1, f. 20. 1864 
Forming on bread a dense, fuscous (Ridgway) turf, 0.1-1 cm. 
tall; sporangiophores 10-16 yw in diameter, profusely branched with 
branches ending in a sporangium and with a septum above point of 
insertion of branch, also septate at irregular intervals in the 
sporangiophores; sporangia globose, 60-80 » in diameter (extremes 
35-117 «), brownish black, encrusted with crystals or smooth; 
sporangium wall deliquescent, leaving a basal membrane; columella 
free, oval, pyriform, elongated, or conical, smooth or furnished with 
one to twelve spines at the apex, 30-60 X 16-32 w (extremes 16- 
74 X 12-59), dark brown; spores globose, 6-9 « in diameter 
(extremes 5-13 u), also a few elliptical and irregular-shaped spores, 
23 X 18, 16 X 12 yu, dark brown, punctate; zygospores not found 
(species heterothallic). 
This species was obtained four times: twice as contamination 
in cultures; from Sphagnum with germinating seeds; and from a> 
decayed Brazil nut. Nos. 47, 51,61, and 78. The species is quite 
variable, as a comparison of the descriptions given by Fischer and 
Lendner will show. Moreover, there are transitional forms be- 
tween it and the closely related species, M. spinescens Lendner. 
On potato agar, rolled oats, and bread, M. plumbeus reaches a 
height of 10 mm., on rice, 7-8 mm., on cornmeal, 5 mm. and on 
grapefruit, 4-5 mm. There is no color production on rice. It 
ferments dextrose and oxidizes tyrosin, but more slowly than 
M. coprophilus and M. griseosporus. 
8. Mucor spHAEROSPORUS Hagem, Vid.-Selsk. Skr. M.-N. KI. 
Christiania 19077: 22. f. 4. 1908 
Forming on bread a dense, 2 mm. high, and a sparse, I cm. 
high, hair brown (Ridgway) turf; sporangiophores 6-18 » in di- 
ameter, typically branched, with one long branch Gin turn pro- 
fusely ramified), or several short, simple branches, in either case 
with branches terminating in a sporangium and with a septum 
above the point of insertion of a branch; sporangia globose, 78-86 yw 
in diameter (extremes 59-98 »), with spores shining through, 
brown; sporangium wall deliquescent, leaving a basal membrane; 
columella free or slightly adnate, subglobose to pyriform, 39-59 
X 35-47 m (extremes 23-70 X 21-59), tinged brown; spores 
uniformly globose, 5-8 x in diameter (extremes 4-10 ), yellowish; 
chlamydospores in sporangiophores, globular, with central oil 
globule; zygospores not found (presumably heterothallic). 
